1

Best Practices

For

Site Supervision

Joint Accreditation Committee

c/o The Institution of Engineers, Singapore

70, Bukit Tinggi Road, Singapore 289758

Tel: 6469 5000 Fax: 6467 1108

Email: re.rto@iesnet.org.sg

2

Foreword & Acknowledgment

Since 15 February 2009, the Joint Accreditation Committee (JAC) of The

Institution of Engineers Singapore (IES) and Association of Consulting Engineers

Singapore (ACES) has been accrediting Site Supervisors (SS) for the site

supervision of structural works. The accredited SS assists the Qualified Person (QP)

in ensuring the high quality and safety of buildings on site is achieved. To effectively

carry out site supervision of structural works, the SS must constantly keep abreast of

the latest construction technology and adopt the best practices in site supervision.

A Technical Committee was thus formed to develop a guidebook on “Best

Practices for Site Supervision” (BPSS) to not only ensure building safety, but also for

the SS to work with the QP, builders and developers to enhance construction

productivity. The BPSS provides simple and practical tips to assist the SS, QP,

builders and developers in achieving high standards of workmanship in building. The

BPSS serves to gather some good practices in carrying out quality supervision of

structural works. It is not meant to be a complete handbook to showcase how site

supervision is to be carried out at site.

3

Technical Committee For Best Practices For Site

Supervision

Chairman : Er. Chong Kee Sen IES

Co-Chairman : Er. Henry Lim Hung Tjung ACES

Secretary : Mr Brendon Ho IES

Members : Mr Alex Pang SCAL

: Ms Quek Chay Hoon REDAS

: Dr. Kannan V Resident Engineer

: Mr Tan Bee Loke Resident Technical Officer

: Er. Tan Chong Lin BCA

: Er. Shee Siu Ming BCA

We trust that the industry will find this publication useful in its pursuit of quality

excellence. We wish to express our gratitude to the members of the Technical

Committee for their contribution in drafting the “Best Practices for Site Supervision”.

Er. Chong Kee Sen Er. Henry Lim Hung Tjung

Chairman Co-Chairman

BPSS Technical Committee BPSS Technical Committee

4

CONTENTS

1. INTRODUCTION

2. THE OBJECTIVES

3. SAFE AND PRODUCTIVE CONSTRUCTION

I Planning for Construction Works

Role of Builder

3.1 Early Involvement for Constructability of Building

Design

3.2 Conduct Pre-construction Survey on Adjacent

Building Properties

3.3 Produce Shop Drawings for Ease of Construction

Role of Qualified Person

3.4 Carry out Risk Assessment on Adjacent Building

Properties

3.5 Prioritise Alternative Building Design for Plan

Approval

3.6 Briefing to Site Supervisor

3.7 Briefing to Builder

3.8 Engage Additional Site Staff for Night-shift Works

Role of Developer

3.9 Provide Adequate Number of Soil Boreholes for

Foundation Design

3.10 Engage More Site Supervisor for Complex

Development Project

Page No

7

7

8 – 11

5

II Execution for Construction Works

Role of Builder

3.11 Compliance with Approved Structural Plans

3.12 Compliance with Workmanship Standard

3.13 Prepare Monthly Site Inspection Schedule

3.14 Engage Construction Supervisor

3.15 Engage a Professional Engineer for the Design of

Falsework

3.16 Notification of Contravention of Building Works

Role of Site Supervisor

3.17 Construction Works Deviated from Approved

Structural Plans

3.18 Detection of Construction Irregularities

3.19 Minimise Abortive Construction Works

3.20 Adhere to Site Inspection Schedule

3.21 Ensuring Falsework is Safe for Use and

Dismantling

Role of Qualified Person

3.22 Safeguard Construction Works to Meet Design

Specification

3.23 Compliance with the Building Regulations

3.24 Checklists for Construction of Complex Structures

3.25 Conduct Essential Tests on Building Materials

3.26 Implement Instrumentation Monitoring Measures

3.27 Verification of Soil Parameters for Design of Piles

11 – 18

6

3.28 Steel Frames/Precast Structures Fabricated Off

Site

Role of Developer

3.29 Avoid Amendment to Approved Building Design

III Completion of Construction Works

Role of Builder

3.30 Submission of Certification of Completion of

Construction

Role of Site Supervisor

3.31 Check the Completed Construction Works

Role of Qualified Person

3.32 Collaborate with Architect for TOP/CSC

Application

4. MOTIVATION AND REWARD FOR SITE

SUPERVISOR

4.1 Performance Bonus for Outstanding Site

Supervisor

4.2 Exemplary Site Supervisor Award

Annex I

Workman Standard for Structural Work

Annex II

Performance Bonus Upon Certification

18 - 19

19 – 20

21 – 36

37

7

1. Introduction

The guidebook on Best Practices for Site Supervision (BPSS) serves to

outline some good industry practices that the developer, builder, site

supervisor (SS) and qualified persons have adopted in carrying out site

supervision of structural works. However, it is not meant to be a complete

handbook to showcase how the site supervision is to be carried out at site.

2. The Objectives

The objectives of the BPSS are to ensure that a high standard of site

supervision in construction is systematically carried out by the project parties,

namely, the developer, builder, site supervisor and qualified persons to

safeguard the structural integrity of the building, and to enhance construction

productivity of a development project. To meet the objectives, the project

parties must play their roles diligently through the following broad frameworks

of the BPSS.

I. To set out good industry practices for construction to ensure safe

buildings are built

II. To motivate the site supervisor work closely with the builder, developer

and qualified persons to enhance construction productivity

III. To reward the site supervisor for achieving high quality and safety

standard of building

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3. Safe and Productive Construction Works

I Planning for Construction Works

Role of Builder

3.1 Early Involvement for Constructability of Building Design

The building design has a significant impact on the constructability of a

development project. A buildable design will enhance construction

productivity and may shorten construction period of a development project.

The builder, specialist builder or their sub-contractors, should be involved in

the early stage of building design to allow sufficient time for the builder to plan

and adopt the most productive construction method to enhance

constructability of the development project.

3.2 Conduct Pre-construction Survey of Adjacent Building Properties

The builder should carry out pre-construction survey with photographs and

report on adjacent building properties. The carrying out of pre-construction

survey should not be limited to building properties immediately adjacent to site

construction. The survey will serve as a useful reference in determining

suitable methods of construction to minimise any damage to nearby properties

caused by the construction works. The builder should consult qualified person

for supervision of structural works [QP(S)] on the extent of pre-construction

survey to be carried out if the construction works are likely to have adverse

effects on the nearby building properties.

3.3 Produce Shop Drawings for Ease of Construction

For ease of construction and to minimise construction error, correct and

accurate construction details are to be reflected in the construction drawings.

9

The builder, specialist builder or their sub-contractors, should employ suitable

qualified staff to constantly review and translate the structural details into

construction shop drawings for construction. If there are discrepancies found

in the approved structural details, these discrepancies should be resolved with

the qualified person for structural works [QP(D)] early in order to avoid

disruption to the progress of site construction works.

Role of Qualified Person

3.4 Carry Out Risk Assessment on Adjacent Building Properties

The QP(D) should carry out risk assessment on adjacent building properties.

However, for carrying out demolition works to existing building, QP(S) should

carry out the risk assessment on adjacent building properties. The QP(S)

should direct the builder to implement safety measures, and to safeguard

structural integrity of these building structures if site construction works are

likely to cause damage to these building structures. In addition, monitoring

instruments have to be installed to monitor the effect of the construction works

on the buildings.

3.5 Prioritise the Alternative Building design for Plan Approval

The QP(D) should engage the builder, specialist builder or their sub-

contractors, early to allow time for them to propose alternative building design

that is more productive and easier to build. By engaging the builder, specialist

builder or their sub-contractors, early, it also allows time for QP(D) to review

and adopt the alternative building design, and to submit the design for plan

approval by the building authority.

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3.6 Briefing to Site Supervisor

The QP(S) should brief the SS that site supervision of structural works should

follow strictly to the approved structural plans, and deviation from the

approved structural details is not allowed unless consent has been obtained

from him. The QP(S) should also regularly brief the SS on issues relating to

site supervision of critical structural works, such as transfer structures, steel

connections joints, etc., highlighting the critical areas for construction to

ensure that a safe construction is carried out. The QP(S) should organise and

delegate the different areas of supervisory duties to each site supervisor in a

supervision team.

3.7 Briefing to Builder

The QP(S) should highlight the statutory role of the builder to carry out

construction works in accordance to the approved structural details, and no

deviation of approved structural details is allowed to be carried out unless his

consent is obtained. The QP(S) should also similarly brief the builder, in the

presence of the SS, on areas of concern for the construction of critical

structural elements of the building structures to ensure that a safe construction

is carried out.

3.8 Additional Site Staff for Night-shift Works

For development project that requires 24-hour working shift, the QP(S) is

advised to appoint additional SS to supervise the construction during the night

shift work. As a good industry practice, there should be a daily record of

handing and taking over the statutory duties of SS between the SS for the

day-shift works and night-shift works.

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Role of Developer

3.9 Provide Adequate Number of Soil Boreholes for Foundation Design

It is important that adequate and accurate soil boreholes information is made

available for QP(D) to design the foundation of the building. As a good

industry practice, there should be at least one soil borehole underneath each

proposed block of building. For project development of 10-storey or more,

reference to BCA’s advisory note on site investigation should be made.

However, if the QP(D) assess that additional no. of soil boreholes are required

to be carried out, the developer should support QP(D) for carrying out the

additional no. of soil boreholes.

3.10 Engage More Site Supervisor for Complex Development Project

The minimum number of SS to be engaged to supervise the development

project is stipulated in the building regulations. However, for a complex

project that requires more supervisors to supervise, the developer and the

QP(S) should work together to engage more SS.

II Execution for Construction Works

Role of Builder

3.11 Compliance with Approved Structural Plans

The builder is statutorily1 required to carry out construction works in

accordance with the structural plans approved by the building authority. The

builder should not carry out any structural works without the supervision of a

QP(S) or the SS. The builder needs to obtain the consent from QP(S) if he

1 Section 11(1)(a)(iii) of Building Control Act – A builder undertaking any building works shall ensure that the building works are

carried out in accordance with the relevant plans approved by the Commissioner of Building Control and supplied to him by a

qualified person under section 9(1)(c);

12

intends to carry out structural works which are deviated from the approved

structural plans.

3.12 Compliance with Workmanship Standard

The builder should carry out construction works to meet the design

specification of the building structures. The builder is advised to follow the

Workman Standard for Structural Works (See Annex I) or any other

workmanship standard to achieve a safe and quality construction at site. The

builder should consult QP(S) if he needs clarification from the Workman

Standard for Structural Works.

3.13 Prepare Monthly Site Inspection Schedule

The builder should prepare a monthly schedule for site inspection by QP(S) or

the SS. The builder should inform QP(S) or the SS at least 24 hours before

the actual day of the site inspection. If the SS for the development project

could not carry out site inspection on the scheduled date, a replacement SS

should carry out the site inspection and the builder should be informed

accordingly.

3.14 Engage Construction Supervisors

The builder is advised to engage qualified construction supervisors to

progressively inspect the construction works to ensure that construction works

are carried out right at the first time as re-working on the completed

construction works will be time consuming and costly. As construction works

are progressively inspected by the construction supervisors, it will be unlikely

to have any major shortcoming detected during the final site inspection carried

out by the SS to approve concreting of the structural elements of the building.

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3.15 Engage a Professional Engineer for the Design of Falsework

A robust falsework is vital to support the construction of building structure,

especially structures with high floor to floor headroom or supporting heavy

loads, etc. Hence, it is important that the builder should engage a professional

engineer (PE) to design the falsework. After the installation of the falsework

but before concreting of the permanent structural elements, the builder should

get the PE to inspect the falsework and to certify that they are safe. The

builder should also obtain the consent from the PE before dismantling the

falsework in accordance with the dismantling procedures as set out by the PE

for the falsework.

3.16 Notification of Contravention of Building Regulations

The builder2 should notify the building authority directly if he notices that there

is contravention of building regulations carried out by other project parties, e.g.

QP carries out material changes to the design of building works without first

obtaining amendment plan approval, etc.

Role of Site Supervisor

3.17 Construction Works Deviated from Approved Structural Plans

It is the statutory role of the SS3 to ensure that the construction works carried

out by the builder follow strictly to the approved structural plans. The SS

should report to QP(S) immediately if the builder proposes to carry out

construction works which are deviated from the approved structural plans.

2 Section 11(1)(b) of the Building Control Act – A builder undertaking any building works shall notify the Commissioner of

Building Control of any contravention of this Act or the building regulations relating to those building works of which the builder

knows or ought reasonably to know;

3 Section 10(5) of the Building Control Act – Every site supervisor appointed under this section in respect of any building works

shall take all reasonable steps and exercise due diligence …..to ensure that the structural elements or critical structural

elements….are carried out in accordance with the plans of building works in accordance with section 9(1)(c) by a qualified

person…

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3.18 Detection of Construction Irregularities

The SS should immediately notify QP and the builder if construction

irregularities are detected at site so that corrective measures can be taken to

rectify the construction irregularities before carrying out the next stage of

construction works at site.

3.19 Minimise Abortive Construction Works

The SS should work closely with the builder and his sub-contractors in

carrying out inspections at different stages of construction. The SS should

regularly check the construction works, and if there are construction

irregularities found during the construction, the SS should notify the builder

and his sub-contractors to rectify them immediately. Frequent inspections

carried out by the SS would minimise any major shortcomings detected during

the final inspection prior to concreting of the structural elements.

3.20 Adhere to Site Inspection Schedule

The SS shall adhere to the site inspection schedule prepared by the builder.

The SS shall notify QP(S) if he could not carry out site inspection on the

scheduled date and time so that alternative arrangement could be made for a

replacement SS e.g. an engineer from the QP’s office to carry out the site

inspection. The SS should work closely with the builder to adhere strictly to

the site inspection schedule to avoid disruption to the overall progress of the

construction works at site.

3.21 Ensuring Falsework is Safe for Use and Dismantling

The SS should allow the builder to cast concrete or laying of reinforcement

bars only after the PE for falsework has inspected and certified that the

15

falsework is safe for use. The SS should also obtain the consent from the PE

for falsework that the structural members have attained sufficient strength to

support the design loads of the building before allowing the builder to

dismantle the falsework in accordance with the dismantling procedures as set

out by the PE for falsework.

Role of Qualified Person

3.22 Safeguard Construction Works to Meet Design Specification

The QP(S) should visit site frequently to ensure that site construction works

are carried out in accordance with the design specification of the building

structures, especially during construction of critical structural elements, such

as transfer structures, critical joint connections in steel structures, etc.

3.23 Compliance with the Building Regulations

It is the statutory role of the QP4 to ensure that the building works are

designed in accordance with the provision of the Building Control Act. The QP

shall also ensure that those building works are being carried out in accordance

with the relevant plans approved by the Commissioner of Building Control.

3.24 Checklist for Construction of Complex Structures

4 Section 9(1)(a)(i) of the Building Control Act – Every qualified person who is appointed under section 8 or 11 to prepare the

plans of any building works shall take all reasonable steps and exercise due diligence to ensure that the building works are

design in accordance with the provision of this Act

Section 9(1)(4)(a)(iii) of the Building Control Act - Every qualified person who is appointed under section 8 or 11 to supervise

the carrying out of any building works, or any geotechnical aspects of any underground building works, shall take all

reasonable steps and exercise due diligence in supervising and inspecting the building works or underground building works, as

the case may be, to ensure that the building works are carried out in accordance with the relevant plans approved by the

Commissioner of Building Control;

16

The QP(S) should prepare checklists, highlighting the areas of concern for the

pile installation, construction of transfer beam and columns, long span steel

trusses and cantilever structures, etc. The QP(S) should brief the SS or the

builder on areas of concern, such as pile set criteria for pile installation,

number and frequency of weld tests for critical steel structures, checking the

audited mills with necessary Factory Production Control certificate and mill

test certificate to ensure reliable quality assurance for the steel used for the

critical steel structures, etc. The QP(S) should regularly check that the

checklists are complied with by the SS and the builder.

3.25 Conduct Essential Tests on Building Materials

In Singapore, many building materials, such as steel bars, structural steel

sections, prestressing wires, etc, are imported. The quality of these materials

can vary significantly depending on the technology used and the quality

control of the manufacturers. Poor quality materials, if not detected, can

undermine the structural integrity of the building structures. It is therefore

important for the QP(S) to require the builder to engage independent testing

agency (ITA) to conduct tests to confirm the quality of these materials. The

QP(S) should also stipulate the number and frequency of such tests to be

carried out by the ITA.

3.26 Implement Instrumentation Monitoring Measures

The QP(S) should instruct the builder or specialist builder to install site

monitoring instruments to measure the effect and performance of the

construction works. The instrumentation monitoring results serve as an early

alarm if the adjacent building properties are affected or the performance of the

17

construction works cannot meet the design specification. Based on the

monitoring results, the QP(S) should immediately stop construction works, and

take corrective measures to rectify the shortcomings.

3.27 Verification of Soil Parameters for Design of Piles

The QP(S) should brief the SS and the builder that piles must be installed in

accordance to approved piling plans. As soil profile may vary significantly at

site, the QP(S) should instruct the builder to install test piles to confirm the pile

design before carrying out piling works. As a good industry practice, the

QP(S) should inspect the soil samples extracted during test piling works, and

instruct the builder to stop piling works if the extracted soil samples are

different from the soil types used for the pile design. In such cases, the QP(D)

should submit amendment piling plans based on the new soil parameters for

approval by the building authority before carrying out the piling works.

3.28 Steel Frames/Precast Structures Fabricated Off Site

For steel frames or precast concrete structures that are fabricated off site in

Singapore or overseas, the QP(S) should appoint another SS to supervise the

construction of these structures off-site. The QP(S) should brief the SS and

the builder to carry out the necessary verification tests on these structures

when these structures are delivered to the site. If the tests fail to meet the

design specification of the building, the QP(S) should insist that more tests to

be carried out on these structures. If the tests still fail to meet the design

specification, the QP(S) should reject the structures delivered at site.

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Role of Developer

3.29 Avoid Amendment to Approved Building Design

Developer should refrain from changing the building design after the

commencement of the construction as construction works may have to be

temporarily suspended while the QP(D) amends the structural details for

construction, and seek plan approval from building authority before the

amendment can be implemented at site. In the circumstance that changing of

the approved building design is necessary, the developer is strongly advised

to allow time for QP(D) to effect the changes to the approved plans before

construction.

III Completion of Construction Works

Role of Builder

3.30 Submission of Certification of Completion of Building

Upon completion of all construction works, it is a statutory requirement for the

builder to submit promptly the as-built drawings of both permanent and

temporary (left-in) structures (temporary shoring structures, kingposts, etc),

and a certificate of completion of building works certifying that all construction

works have been carried out in accordance with the approved structural plans.

The builder should not withhold the submission of the certificate of completion

because of disputes on payment by the developer. The submission of

certificate by the builder is important for the application of Temporary

Occupation Permit (TOP)/Certificate of Statutory Completion (CSC).

19

Role of Site Supervisor

3.31 Check the Completed Building Works

The SS shall check that the constructed structural elements comply with the

technical design specification of the development project. If sub-standard

structural works were noted at site, the SS shall report to QP(S) with attached

photographs of those sub-standard structural works to seek instruction from

QP(S) on the rectification of those sub-standard structural works.

Role of Qualified Person

3.32 Collaborate with Architect For TOP/CSC Application

The QP should promptly submit the relevant record plans and certificates of

supervision upon completion of all building works to assist the architect for the

TOP/CSC application. The QP should also work closely with the architect to

obtain all necessary technical clearances leading to the application for the

TOP/CSC.

4. Motivation and Reward for Site Supervisor

4.1 Performance Bonus for Outstanding Site Supervisor

The SS plays an important role in ensuring that a high standard of

workmanship of the building works is achieved as the cost of rectification

works is high if sub-standard building works are produced. To motivate the

SS to play the role, the developer is encouraged to reward the SS with

performance bonus through the QP if high standard of workmanship (See

Annex I) and construction productivity of building works are achieved.

Payment of performance bonus (See Annex II) may be made upon certificate

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of the Structural Conquas Score from BCA in compliance with standard of

workmanship as in Annex I

4.2 Exemplary Site Supervisor Award

To motivate the SS to work closely with the builder, developer, and the QP(S)

to ensure safe construction of building works, the Joint Accreditation

Committee (JAC) of the Institution of Engineers, Singapore (IES) and

Association of Consulting Engineering, Singapore (ACES) has introduced the

“Exemplary Site supervisor Award” for outstanding SS. Nomination of the SS

for this award has to be made by the QP of the project. Both the builder and

developer of the project should also give favourable appraisals to the SS

before he can be qualified for this award. JAC shall reward the exemplary SS

with training or cash vouchers. In addition, the names of the exemplary SS

will also be published in IES website to enhance their employability. The

developer or the QP(S) is encouraged to individually reward the SS if their

performance is commendable.

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Annex I

WORKMAN STANDARD FOR STRUCTURAL WORK

Part I : REINFORCED CONCRETE STRUCTURE

Item *Acceptable Standard

1.0

1a

1b

Formworks

Formwork

dimensions and

openings for

services

Alignment, plumb

and level

1) Tolerance for cross-sectional dimensions of

cast in-situ & precast elements: ±10mm

2) Tolerance for penetration / opening for

services: ±10mm for size and ±25mm for

location

3) Tolerance for length of precast members

(major dimension of unit):

• Up to 3m: ±6mm

• 3m to 4,5m: ±9mm

• 4,5m to 6m: ±12mm

• Additional deviation for every subsequent 6m:

±6mm

1) Tolerance for departure of any point from its

position: ±10mm

2) Tolerance for plumb: ±3mm I m, maximum

±20mrn

3) Maximum deviation of mean level of staircase

22

1c

Condition of

formwork, props &

bracing

thread to temporary bench mark: ±5mm

4) For cast in-situ elements, the deviation of

level of any point from the intended level:

±10mm

1) Formwork must be free from defects

2) Before concreting, the interior must be free

from debris

3) All formwork joints must not have noticeable

gaps to prevent grout leakage

4) There must be adequate support, bracing and

tie-back for the formwork to prevent bulging or

displacement of structural elements

2.0

2a

2b

2c

Reinforcement (cast

in-situ & precast)

Main & Secondary

rebars

Anchorages & lap

lengths

Cover provision

1) According to structural drawings (numbers /

sizes)

2) Spacing of bars not more than that specified

1) Required lap length not less than that

specified

1) According to specifications with tolerance of

±5mm

23

2d

2e

Links, stirrups and

trimming bars

Rebar Condition

1) According to structural drawings (numbers /

sizes)

2) Spacing of links not more than specified

1) Rebars must be securely and properly tied In

place

2) Rebars must be freed from concrete dropping,

corrosion etc

3.0

3a

Finished Concrete

(cast in-situ &

precast)

Dimension for

elements/opening

for services

1) Tolerance for cross-sectional dimension of

cast in-'situ and precast elements: ±10mm

2) Tolerance for opening: ±10 for size and

±25mm for location

3) Tolerance for length of precast members

(major dimension of unit):

• Up to 3m: ±6mm

• 3m to 4.5m: ±9mm

• 4.5m to 6m: ±12mm

• Additional deviation for every subsequent 6m:

±6mm

4) Straightness or bow (deviation from Intended

24

3b

Alignment, plumb

and level

line) of precast member:

• Up to 3m: ±6mm

• 3m to 6m: ±9mm

• 4.5m to 6m: ±12mm

• Additional for every subsequent 6m: ±6mm

5) Squareness of precast member -Difference

between the greatest and shortest dimensions

should not exceed the following:

Length of shorter sides

• Up to and including 1.2m: ±6mm

• Over 12m but less than 1.8m: ±9mm

• 1.8m and over: ±12mm

6) Twist of precast member -Any corner should

not be more than the deviation stated from the

plane containing the other 3 corners:

• Up to 600mm wide and 6m in length: ±6mm

• Over 600mm wide and for any length: ±12mm

7) Flatness: 6mm per 1.5m

1) Tolerance for departure of any point from its

position: ±10mm

2) Tolerance for plumb: ±3mm / 1m, maximum

±20mm for floor to floor height and ±40mm for

the entire building height

25

3c

Exposed surface

3) Maximum deviation of mean level: ±10mm

4) For cast in-situ elements, the maximum

deviation of levels within the element: ±10mm

5) Camber at mid-span: according to

specifications

1) Should not have visual exposure of groups of

coarse aggregates resulting from grout

leakage

2) Cold joint & formwork joint must be smooth

3) No bulging of structural elements

4) All formwork, nails, zinc strips, etc must be

removed

5) No cracks or damages

4.0

4a

4b

Precast Specific

Requirements

Lifting

points/inserts

Sleeve

system/connections

1) Tolerance for position: ±20mm from centre

line location in drawing

2) Lifting devices and inserts free from damages

1) Tolerance for position: ±6mm from centre line

location in drawings

26

4c

4d

Interface/joint

requirements

Cast-in steel

items/welded &

bolted connections

2) Bar protrusion length according to

requirements. No bending, cranking or

damages to bars

3) Bars free from concrete droppings or

corrosion

4) Sleeves, grout holes, grout tubes not

congested with debris

1) Joint taper:

• Over 3m length: ±6mm

• Maximum for entire length: ±9mm

2) Alignment of horizontal and vertical joint

±6mm

3) Jog in alignment of matching edges: ±6mm

4) Sitting of element according to specifications

5) Installation of sealant and waterproofing:

according to specifications

1) Tolerance for position of cast-in steel Items:

±6mm from centre line location in drawings

2) Tolerance for position of openings for bolt

connections: ±3mm from centre line location

in drawings

3) Relevant requirements in CONQUAS

27

steelwork standards to be used where

applicable

5.0

5a

5b

Structure Quality

Concrete Cube Test

Reinforcement

1) According to specifications; for every pour of

concrete, test cubes results at 28 days must

satisfy the passing criteria as in SS289

1) To pass the tensile strength test for all the

reinforcement bars used as according to:

• -SS2:1999 for Grade 500 ribbed bars or

• -SS2:1987 for Grade 460 ribbed bars

2) All the welded steel fabric used to comply with

SS32 in their respective specified

characteristic strength of not less than 250 N

per mm2, 460 N per mm2 and 485 N per mm2

3) No non-conforming reinforcement detected

through test records has been installed in the

structure

6.0

6a

Non-destructive

testing

Ultra Pulse Velocity

test for Concrete

Uniformity

1) To conduct NDT using ultrasonic pulse

velocity (UPV) to check the degree of

uniformity of hardened concrete

2) 5 columns per set and 2 readings per column

28

6b

Electro-Cover meter

test for concrete

cover

3) Assessment is based on the difference

between the 2 UPV readings within a column

shall not exceed 0.05 km/s

4) Method as per SS 78 : Part B3 : 1992

1) To check hardened concrete cover for

reinforcement bars after casting: minimum

25mm or higher as according to specification

2) 5 structural samples per set including:

• 3 for slab soffit @ 4 readings each

• 1 for column @ 2 readings each on both axis

of the column

• 1 for beam @ 2 readings each on the soffit

and one side of the beam

3) For each reading, full point for ±5mm and half

point for >±5mm to ±8mm. For each location,

no point will be awarded if any of the 4

readings exceeds ±12mm.

4) Method as per SS 78 : Part B4 : 1992

29

Part II : STRUCTURAL STEELWORKS

Item *Acceptable Standard

1.0

1a

1b

1c

Main

member/Partial

assembled

component

Physical

dimensions

Type and condition

Welding

1) Cross sectional tolerance should not be less than

the structural steel specifications or approved

plan

2) Tolerance for length of structural steel member:

±3mm

3) Tolerance for bolt hole size:

• ≤2mm for bolt diameter < 24mm

• ≤3mm for bolt diameter ≥24mm

Tolerance for bolt hole position: ±2mm

1) According to the structural steel specifications

2) Surface preparation shall meet the surface

roughness specifications

3) Material used must be traceable to its original mill

certificates

1) Weld size, length and profile shall meet the

structural steel specifications and drawings

2) Visual inspection shall meet the structural steel

30

1d

Bolting

specifications

3) All weld shall follow approved welding procedures

4) All welding must be done by qualified welders

1) Bolts and washers, type, size and number shall

be according to the structural steel specifications

2) Drilled holes shall be free from burrs

3) The condition of bolted parts adjacent to the bolt

heads, nuts, flat washers, connection gussets

and splice plates shall be free from oil, paint, and

loose mill scales or otherwise specified by the

structural steel specifications

4) Gap between adjacent parts shall not exceed

±2mm

5) Bolts shall be tightened to specified torque or as

specified by the structural steel specifications

6) Threaded bolts protruding at least one thread

length with washers

2.0

2a

Metal decking

Type and condition

1) Correct type and thickness of metal decking used

2) All decking joints must not have gaps

31

2b

2c

Shear studs

Lapping and deck

openings

3) All metal decking must be properly secured in

place

4) Metal decking must be free from defects and

visible damages

5) Before concreting, the decking must be free from

grease, oil, paint, and all other foreign materials

6) All accessories such as pour stop, end closures

and cover plates must be in place before

concreting

1) Correct number and type of shear studs used

2) Spacing and position according to approved plan

3) Strength of shear stud welds not less than

specified

4) All welds should show a full 360-degree weld

fillet. All welds free from visible damages

1) According to structural steel specifications or

approved plan

3.0

3a

Erection

tolerances

Column verticality

1) Tolerance for verticality: ±H/600 or 5mm,

maximum ±25mm; where H is the floor to floor

height in mm.

32

3b

3c

3d

Column position

Beam level

Beam position

1) The position in plan of a steel column at the base

shall not deviate from the specified position by

more than 10mm along either of the principal

setting out axes

1) Maximum deviation of level at each end of the

same beam: ±5mm

2) The level of the top of the steelwork at any storey

shall be within ±10mm of the specified level

1) Beams shall not deviate from their specified

positions relative to the column to which they are

connected by more than 5mm

4.0 Welding test

reports

1) Reports for all critical welding joints from the

approved structural plans must be submitted

2) Test reports must comply with the acceptable

criteria and to be endorsed by qualified person for

structural works

33

Part III : PRE-STRESSING OF CONCRETE

item *Acceptable Standard

1.0 Condition of

tendons &

anchorages

1) All pre-stressing strands and wires should

comply with the specified standards and

requirements and be free from loose rust, oil,

tar, paint and any foreign objects

2) All tendon anchorage are to comply with the

specified standards and protected from

corrosion

Thread parts to be greased wrapped and

tapped holes protected until use

2.0 Installation of

sheathing

1) Sheathing properly secured and protected and

free from damage or puncture

2) Sheathing profile according to drawings

throughout the length with position tolerance:

±5mm

3) Splice to sheathing shall be mortar tight

4) Air vents or grout tubes provided according to

the drawing

3.0 Stressing &

Grouting process

1) Tendon ducts clean and free from foreign

objects and tendon free moving in the duct

2) Strands stressed to the final pressure /

elongation within the specific % accuracy of the

34

stipulated value

3) All grouting operations of the tendons must be

smooth and achieved without need to flush out

in the first grouting.

4.0 Debonding 1) Open ends of debond tubes over the debond

length of strands sealed

2) Debond lengths according to the drawings

3) Debonding materials not punctured or

damaged

35

Part IV : FOUNDATION WORKS

Item *Acceptable Standard

1.0

1a

1b

1c

1d

Shallow

Foundation

Setting out

Safety of

excavation

Trial Pits

Excavated

material

1) Sufficient lines and level pegs are provided to

enable each footing and column to be

accurately positioned.

1) Temporary earth retaining structure is provided

if for the purpose of pilecaps, footings, sump,

lift pit or trench, the depth of excavation is more

than 2m in depth and the area of excavation

exceeds 10m2

1) Sufficient trial pits are required before works is

carried out to

a. inspect and confirm that the founding soil layer

is suitable for the foundation design

b. determine the location and extent of existing

foundation and services

2) No new foundation is constructed over existing

foundation and services without the approval of

the qualified person.

1) The excavated material shall not store in a

manner likely to endanger the excavated or

36

1e

Backfilling

material

surrounding areas.

1) All backfilled material shall be free of debris,

and of good material soil

2.0

2a

2b

2c

2d

2e

Piling Works

Setting out

Piling method

Piling

performance

criteria

Install Instruments

Testing piles

1) The setting out of all piling works are certified

by registered surveyor.

1) Details of piling method are provided to

qualified person for him to assess the suitability

of the piling method before commencement of

piling works

1) Piling works are carried out to meet the piling

performance criteria that are stipulated in the

approved piling plans

1) Appropriate instruments are installed to monitor

the piling works to avoid damages to adjacent

structures, underground services, etc.

1) All piling tests are carried out according to the

stipulated piling tests on approved piling plans

or are instructed by the qualified person

*Acceptable Standard is meant to be a guide for measuring the level of workmanship of construction. Ultimately, the qualified

person for supervision works shall decide the acceptable standard to be used in meeting the technical design specification of

the development project.

37

Annex II

Performance Bonus Upon Certification (example)

Structural Conquas Score Performance Bonus

94.6% to less than 96% 1 month Salary

96% to less than 98.4% 1.5 months Salary

98.4% and above 2 months Salary